body {
  position: absolute;
  left: 0;
  right: 0;
  top: 0;
  bottom: 0;
  background-color: #eee;
  padding: 0 0 0 0;
  border-width: 0 0 0 0;
}

div {
  box-sizing: border-box;
}

.top-nav {
  height: 30px;
  width: 100%;
  padding: 10px 12px 10px 12px;
}

.top-nav > a {
  position: relative;
  display: inline-block;
  text-decoration: none;
  font-size: small;
  color: #000;
  background-color: #f6f7f8;
  border:rgb(93, 93, 93) solid 1px;
  border-radius: 3px;
  padding: 5px 15px 5px 15px;
  z-index: 9;
}

.top-nav > a:hover {
  color: rgb(93, 93, 93);
}

.nav-back {
  position: absolute;
  top: 17px;
  height: 16px;
  left: 0;
  right: 0;
  border-top: 1px dotted #8c8b8b;
  border-bottom: 1px dotted #8c8b8b;
  z-index: 1;
}

.vertical-space {
  height: 15%;
  width: 100%;
}

.center-panel {
  position: relative;
  width: 640px;
  height: 360px;
  margin: 0 auto 0 auto;
}

.img-card {
  width: 640px;
  height: 360px;
}

/* 图片正反面翻转效果 */
.img-card img {
  position: absolute;
  top: 0;
  left: 0;
  transition: all 1s;
}

.img-card .img-front {
  z-index: 1;
  backface-visibility: hidden;
}

.img-card:hover img {
  transform: rotateY(180deg);
}

/* END 图片正反面翻转效果 */

.bottom-bar {
  position: absolute;
  bottom: 0;
  min-height: 42px;
  width: 100%;
  background-color: rgb(34, 34, 34);
  text-align: center;
  line-height: 42px;
  z-index: 9999;
}

.bottom-link {
  color: rgb(93, 93, 93);
  text-decoration: none;
  font-size: 14px;
}

#beianImg {
  vertical-align: text-bottom;
}

.bottom-right {
  color: rgb(93, 93, 93);
  padding-right: 15px;
  display: inline;
  float: right;
}

@media (min-width: 576px) {
  .extra-small-display {
    display: none;
  }
}

@media (max-width: 640px) {
  .center-panel {
    width: 256px;
    height: 144px;
  }

  .img-card {
    width: 256px;
    height: 144px;
  }

  .img-card img {
    width: 256px;
    height: 144px;
  }
}
